Potable water is an essential requirement for all human beings, and ground water remains an essential source of drinkable water. Unfortunately, the increasing world population and continued strides in industrialization have resulted in numerous waste products that embody tangible threats to ground water supplies. In order to detect such undesirable products, ground water is routinely tested for a number of contaminants that are known to be harmful to mankind. Although such tests are extremely accurate, they directly depend upon the manner in which the water sample is acquired. To avoid erroneous results, it is essential that no extraneous contaminants be introduced into the sample taken. Thus, any ground water sampling system must provide both a "clean" (i.e. contaminant free) sampling apparatus for taking a water sample, and a cleaning apparatus for cleaning the sampling apparatus.
Certain factors also contribute to the efficiency of water sampling systems. Due to the wide spread, and sometimes remote locations of monitoring wells, it advantageous for water sampling systems to be easily transportable. Overly heavy or bulky systems can limit the areas in which sampling can be performed and increase the cost and effort needed. A degree of simplicity in design is also desirable as overly complex systems can require a great amount of cleaning, repair, and maintenance, and can also require operators to undergo special training programs to learn how to properly operate the apparatus. To reduce sampling time it is also desirable to have a system wherein once the components are cleaned, they can be stored, and remain clean until required at a later time.
An important aspect of ground water sampling procedures is the initial evacuation of the sampling well. Prior to lowering a sampling device into the well, the well is evacuated by a pump. Once the well is evacuated more water to flows back into the well. It is this water that is sampled as it is considered a more accurate representation of the ground water at that location. Both prior to evacuation, and after evacuation, it is desirable to have clean equipment, to ensure accurate results.
While pumps have been produced which conform to administrative requirements for materials acceptable for use in ground water monitoring, materials used for hoses remains a problem. Approved years ago for ground water monitoring, polytetrafiouroethylene (TEFLON.RTM.) is widely available, but expensive, and subject to undesirable adsorption and absorption characteristics. Alternate hose materials are often difficult to decontaminate.
A number of systems are present in the prior art aimed at ground water sampling, general equipment cleaning, and equipment storage. U.S. Pat. Nos. 5,211,203 and 5,323,800 both issued to Vollweiler et al. on May 18, 1993 and Jun. 28, 1994, respectively, present a portable ground water testing assembly. The assembly of the Vollweiler et al. patents provides a unique, self contained structure having a hydraulic system for driving a boom, and a number of hydraulically driven spools mounted on the boom. The boom includes a spool end for mounting a storage spool and a sheave end for mounting a sheave. A hose and an associated pump are wound onto the storage spool. When the Vollweiler et al. apparatus is in sampling operation, the pump and a portion of the hose are unwound from the spool and onto the sheave. The boom is pivoted so that the sheave end is positioned above a well and the storage spool is unwound, allowing the pump and hose to descend into the well. The apparatus of Vollweiler et al. is complex however, requiring a hydraulic pump and a control system for managing the many functions of the boom. This results in increased maintenance and repair costs, and increases the opportunity for generating contaminants due to the hydraulic fluid and numerous lubricants requires. In addition, the boom itself is a heavy structure increasing the overall weight of the system. The assembly illustrated in Vollweiler et al. is also an "open air" system, that is, it lacks a protective enclosure. The absence of protective enclosures greatly increases the probability that all system components, including those which enter the ground water, will collect unwanted contamination while the system is being transported from common airborne contaminants, such as mists, vapors, gases, fumes and particulate matter of all types, that are present in especially heavy concentrations along roads and highways.
Removing contaminants associated with transportation is complicated in present art systems, such as the assembly illustrated in Vollweiler et al., by the arrangement in which the hose is cleaned automatically as it is drawn out of the well and wound onto the reel. This arrangement assumes that a single pass through the spray box will completely decontaminate the hose. Even though the hose can be given a second pass through the spray box as the pump and hose are deployed into the next ground water monitoring well, this only extends the cleaning to a maximum of two passes of the hose through the spray box. This limitation places significant demands on the ability of the spray box to remove all possible contaminants in two passes. In the case of contamination which collects on the components during transport, cleaning is limited to a single pass which occurs as the hose is unwound from the reel, passed through the spray box and lowered into the next well to be monitored. Thus, the decontamination process of Vollweiler et al. is largely dependent on the availability of a ground water well into which the pump and hose assembly can be lowered. Moreover, the full length of the hose will not be cleaned if the available wells are not deep enough to receive all the hose from the reel or have some other characteristics which make their use inadvisable. This means that recently cleaned sections of hose will be wound onto the reel with hose which has not been cleaned.
A truck mounted cleaning system is set forth in U.S. Pat. No. Re: 27,874 reissued to Fisco, Jr., dated Jan. 8, 1974. The Fisco, Jr. patent illustrates a shroud apparatus for coveting a sewer cleaning system that is primarily aimed at preventing the components of the system from freezing in cold weather. While the Fisco, Jr. apparatus includes an easy opening rear closure member, the apparatus is not adapted for keeping the components within contaminant free.
A truck washing system employing a hose wound reel is illustrated in U.S. Pat. No. 4,784,166 issued to Brager et al. on Nov. 15, 1988. The truck washing system includes a hydraulic circuit for providing movement to the system, resulting in a self-contained, compact unit. While the hydraulic circuit operates with water as a fluid, eliminating potential contaminants presented by petroleum based fluids and lubricants, the apparatus requires a pressured source of water for the hydraulic circuit. In addition, the washing system provides no apparatus for cleaning the hose itself.
None of the prior art addresses the need for a ground water sampling system that provides a easily cleaned water sampling apparatus that can be securely stored, is easily maintained, and that is also easy to operate.